Mason Kortz (PAL/CCE)
The LTER Unit Registry is an online database designed to help information managers and other LTER users query, create, and maintain lists of scientific units. With a scheduled launch of spring 2010, it seems like a good time to start talking about how users will interact with the registry. Currently, we have two products planned for launch. The first is the Unit Registry Web Service, a development tool targetting users designing their own unit-aware applications. The second is the Unit Registry Interface, a web site that allows users to interact with the registry through a simple graphic user interface.
Unit Registry Web Service
The Unit Registry Web Service is a REST service currently in development by the Unit Working Group. This service accepts HTTP requests for information about scientific units and quantities and their usage by LTER sites. Requests may be made for all units, a single unit using a unique identifying number, or a set of units using search filters. The service returns information in an XML or JSON document, depending on the type of request sent.
The Unit Registry Web Service allows the registry to be used in community developed applications at both the site and network level. The service provides a tool similar to an API, but with the advantage of centralized data storage and maintenance. This provides developers with access to the contents of the Unit Dictionary and the query functionality of the Registry. The service can be used in any development environment that allows opening of files over HTTP, including C, PHP, Perl, Java and most other programming languages, as well as analysis tools such as Matlab and R.
The Unit Registry Web Service is intended for use by information managers who are developing data systems and tools that require scientific units. In comparison to a site-specific unit database, the service reduces development time by providing functionality and promotes standardization by serving a single body of content. As a centralized development tool rather than a centralized application, the service allows sites to develop solutions for local needs while leveraging the combined content of the LTER network.
Unit Registry Interface
The Unit Registry Interface is a web site that presents a graphic user interface to the Unit Registry. It provides the same search capabilities as the web service, but inputs are controlled by web forms instead of by HTTP requests, and the results are displayed in human-readable format. The form elements on the site permit multiple query results to interact with each other, allowing advanced options such as searching within previous results or viewing the union of two result sets. Search results can then be downloaded in common formats such as CSV, Excel, or XML.
The Unit Registry Interface is one use case of the Unit Registry Web Service. Thus the inputs and outputs of both interfaces[??], while different in presentation, access the same body of content. Developers using the web service can use the interface to verify query results. Also, the code for the interface is available via subversion from the LTER Network Office servers, so developers can use the Unit Registry Interface as a working example for how to create a web application that uses the Unit Registry Web Service.
The Unit Registry Interface is designed for information managers, researchers, and members of the public who want to use the registry as an application rather than a development tool. As a centralized application, it allows access to the units used by all LTER sites in a user-friendly way. This is intended to meet the most common query and download needs of LTER users without requiring extra development time at the site level.
More information about the Unit Registry can be found on the LTER IM forums at:
http://intranet.lternet.edu/im/forum/7